Image sensors have become ubiquitous. They are widely used in digital still cameras, cellular phones, security cameras, as well as, medical, automobile, and other applications. The technology used to manufacture image sensors has continued to advance at a great pace. For example, the demands of higher resolution and lower power consumption have encouraged the further miniaturization and integration of these devices.
In modern image sensors, color imaging is often accomplished by fabricating a color filter layer on the surface of the image sensor device. The color filter layer typically uses red, green, and blue color filters arranged into a pattern which allow missing color signals to be interpolated using a demosaicing algorithm. This technique allows for the reconstruction of color images resulting in little distortion to the final image.
However, despite advancements in color imaging, image sensors still may produce imperfect color signals for a variety of reasons. For instance, optical cross talk (i.e., the wrong color of light reaching a photodiode intended to receive another color of light) may cause certain colors to become artificially enhanced. Electrical cross talk (i.e., electrons flowing between two separate pixels) may result in image noise.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.